An arrangement in which a V-shaped block (metal element) is formed so as to have rocking edges in two steps at different levels in the height direction of the V-shaped block, and the lower step rocking edge among these rocking edges and a band-wound face (saddle face) within a band-assembly groove (ring slot) against which an inner peripheral face of an endless band (metal ring assembly) abuts are positioned at the same level in the height direction of the V-shaped block is known from Patent Document 1 below.
Due to this arrangement it becomes possible to prevent frictional loss by maintaining constant relative positions, in the direction of travel, on the band-wound face of adjacent V-shaped blocks between a pulley-wound region and a linear region of the endless band, and it also becomes possible, even when the pulley-winding diameter of the endless band changes from a large diameter to a medium diameter and to a small diameter, to accordingly change the relative inclined positions of adjacent V-shaped blocks owing to the rocking edges formed in two steps having different levels, thereby suppressing the amount of core displacement of the endless band between pulleys accompanying a change in speed.
Furthermore, a transmission belt (metal belt) in which a rocking edge, which is the center of rotation of adjacent elements that abut against each other, is formed at a position separated further toward the inner peripheral side than a saddle face of the element, at least one slit part housing a sub ring binding a plurality of elements arranged in an annular manner being formed further radially inside than the saddle face in the radial direction of the ring is known from Patent Document 2 below.
In accordance with this arrangement, since the elements can be bound not only by layered rings (metal ring assembly) layered on the saddle face but also by the sub ring inserted into the slit part, the total number of rings for binding the elements can be increased by at least one, and because of this the durability and the torque capacity of the transmission belt can be improved. Furthermore, since the sub ring inserted into the slit part is disposed at a position closer to the rocking edge than the other layered rings are, the friction between the sub ring and the slit part is small, and it is possible to prevent or suppress friction due to the number of rings being increased, any accompanying power loss, and degradation of the power transmission efficiency.
Moreover, an arrangement in which a rocking edge and a saddle face of an element are made to coincide, and when shaping the element by press forming such as punching out, the rocking edge is provided on a face on the side where a sharp edge can be formed is known from Patent Document 3 below.
In accordance with this arrangement, since the rocking edge of the element can be formed on the sharp edge, which is not influenced by ‘rollover’ when carrying out press forming, for example, it becomes possible to form the rocking edge and a face that the inner peripheral face of a ring abuts against when the ring is wound around the element at substantially the same position in the height direction of the element. As a result, relative slippage between the rocking edge and the inner peripheral face of the ring can be reduced, and frictional loss due to relative slippage can be decreased, thus improving the transmission efficiency of the transmission belt (metal belt).